Inflation Calculator

About the Inflation Calculator

This inflation calculator shows how an amount of money changes in nominal value over time and what the same amount would be worth in today's purchasing power. Enter a starting amount, the expected annual inflation rate, and the number of years, and the tool returns the nominal future value (what today's amount becomes after inflation) and the real value (what today's amount would buy in today's dollars after n years of inflation).

Inflation is the gradual erosion of money's purchasing power. The U.S. Consumer Price Index (CPI) averaged about 3.2% annual inflation from 1925 to 2024, but the rate has varied widely: 1.4% in 2020, 4.7% in 2021, 8.0% in 2022, 4.1% in 2023. Long-term planning should use 2.5-3.5% as a reasonable average; high-inflation scenarios should use 5-8%.

The calculator exposes both directions: how $1,000 grows to $1,370 over 10 years at 3.2% (nominal value, what you'd have if you'd kept the cash under a mattress and inflation pushed wages and prices up), and how $1,000 today would be worth only $731 in 10 years at 3.2% inflation (real value, what today's $1,000 would buy in 10 years). The two numbers are reciprocals.

How It Works

Nominal future value (what a cash amount grows to under inflation):

FV_nominal = PV * (1 + r)^n

Real future value (what today's amount would buy after inflation erodes its purchasing power):

FV_real = PV / (1 + r)^n = PV * (1 + r)^(-n)

Where:

• PV = present value (today's amount)
• r = annual inflation rate (as a decimal)
• n = number of years

The purchasing power lost is the percentage decline in real value: ((PV - FV_real) / PV) * 100. At 3.2% over 10 years, this is 26.9% — meaning $1,000 today would have the buying power of $731 in 10 years, losing 26.9% of its real value.

For an investment to beat inflation, its nominal return must exceed the inflation rate. The real return is approximately nominal_return - inflation_rate (more precisely, (1 + nominal) / (1 + inflation) - 1).

Worked Examples

Suppose you have $1,000 today and inflation runs at 3.2% annually for 10 years.

1. Nominal future value: $1,000 * (1.032)^10 = $1,000 * 1.3702 = $1,370.24
2. Real future value: $1,000 / 1.3702 = $729.87
3. Purchasing power lost: ($1,000 - $729.87) / $1,000 = 27.01%

This means: if you hid $1,000 under a mattress today and prices rose 3.2% annually for 10 years, in 2034 your $1,000 would still be $1,000 in cash but would only buy what $730 buys today — a 27% loss of real purchasing power.

Now compare with a savings account earning 4% nominal: real return = 4% - 3.2% = 0.8% real (more precisely: (1.04/1.032) - 1 = 0.775%). Over 10 years, $1,000 grows to $1,480 nominally but only $1,080 in today's dollars — barely beating inflation.

For retirement planning, the inflation calculator is essential: a $1M retirement target in 30 years at 3% inflation is worth only $412K in today's dollars. Plan in real (today) dollars for clarity.

When to Use This Tool

Use this inflation calculator when:

• Adjusting salary expectations or contract escalators for inflation
• Projecting the real value of a fixed pension or annuity payment over time
• Computing the real return on an investment after subtracting inflation
• Planning long-term financial goals (retirement, college) in today's dollars
• Adjusting historical prices to today's dollars (e.g., 'a $5,000 car in 1970 is equivalent to $X today')
• Demonstrating why keeping cash under a mattress is a guaranteed loss
• Comparing fixed-rate debt (which inflation erodes the real value of) against inflation-protected assets

For adjusting a specific dollar amount from a past year to today, you'll want a CPI-based calculator using actual historical inflation data. This tool uses a fixed assumed rate for forward-looking projections.

Limitations & Disclaimer

This calculator uses a fixed annual inflation rate for the entire projection period, which is unrealistic — actual inflation varies year to year and can be highly volatile (e.g., 8% in 2022 vs 1.4% in 2020). It does not use actual historical CPI data, which is required for converting past dollar amounts to today's dollars. The calculator applies the same inflation rate to all categories of spending, but real inflation varies by category (healthcare and education typically rise 4-6%/year, electronics often decline). For tax brackets and Social Security, the IRS and SSA use specific inflation measures (chained CPI-U and CPI-W) that differ slightly from headline CPI. This is an educational projection tool, not economic forecasting. See our disclaimer for full terms.

Frequently Asked Questions

Last updated: July 21, 2026  ·  Author: HT99 Tools Editorial Team  ·  Reviewed by: HT99 Tools Editorial Team